We also call it the historical present, narrative present, or dramatic present. It means we use the present tense to narrate or tell past events. We use the historical present to make past events seem more dramatic.
* In The Grapes of Wrath, Tom Joad is walking across the cracked, water-starved fields after his release from prison.
* In the classic film, Casablanca, Elsa asks Sam to play "As Time Goes By." At first he refuses.
Either example could have been written in simple past tense. This is your choice as the writer. "In The Grapes of Wrath, Tom Joad walked across. . .”
I may choose the historical present tense
if it makes a past event more dramatic.